From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2D1B0CDB47E for ; Thu, 19 Oct 2023 03:36:06 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qtJoc-0002qe-SD; Wed, 18 Oct 2023 23:35:18 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qtJob-0002qM-EZ for qemu-devel@nongnu.org; Wed, 18 Oct 2023 23:35:17 -0400 Received: from mail-pj1-x1036.google.com ([2607:f8b0:4864:20::1036]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qtJoY-0006qP-U4 for qemu-devel@nongnu.org; Wed, 18 Oct 2023 23:35:17 -0400 Received: by mail-pj1-x1036.google.com with SMTP id 98e67ed59e1d1-27d4372322aso3818068a91.3 for ; Wed, 18 Oct 2023 20:35:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1697686513; x=1698291313; darn=nongnu.org; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=XxYUoOFyAJNHyVXhNR6HdTghDr/N0IJWKv1SyyBKg9E=; b=NUurRsoR3H6q9yHK/6d881L3PyOR0GZ0iNhU1Xr1KJh1x9KjIPGJjwXCQGhkdsQSJb urQEyHQtdXIIxpBZVm/svARbiJbsQVmUQ9mOZ2ssacundFtycckXYMSNLH1c9OwZbLYu fMU/ExC04KHQOcXL5WuuyaWoT8HVbypJHajOUKiBHQnwB8H/rvDb7ZxxQtIUNmeI6hF2 YTk3wb1nHdVY3oYGJoaoFulSaCoa4qKbHAvCSjMb0yfvLDQH/J50hiwbQOgCqR5shGPD v5BIdpWcXWGiRHKmfbRRmPMFkwNM3+imiwRefN08BKu/jCsapTpCdgUccnNP1lizoS/r GH+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697686513; x=1698291313; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=XxYUoOFyAJNHyVXhNR6HdTghDr/N0IJWKv1SyyBKg9E=; b=TjmW19tVj6kMX49cQWmnOOFxXnsbuvGN01tJrxRT1dP0wAkVhUXbi//yeJvjxhLYaI U/1aIQ/6iL4/iydSUXBdjYKS8HYt3/cn+H0PH5Pb1npW3FDt4MiUrDa/3l+LHVfJxLKS 00jfqjt/T0DcC6Qygi0dVaDiPzzX/ImMv16O1ZSx/CNd3Acsk0Bexc4uchQhYO9jk9TX EJUVlgTIFcDd7P0Y+V77RK8xohk9gOVBDUiWduXYwBg0nW8c+P2q4F92Q2TXmdgDboHg lo+8bwC4VV1sPpnNSS6l4B41ckWlbb3uTeQL4hDk052BLPXTS1CevjJzK/Jn6xf8SvZt A0Cw== X-Gm-Message-State: AOJu0YwOnIZicvJoVuQ4VxZkQpX8ZT+qyew1ho/oRauKHPy/evo2GyBs EwvksGI4puQpujJAVOZ7pvZrX1DikD9hdJYHoh0= X-Google-Smtp-Source: AGHT+IFPovUR3NjkMCMTEaGgr6uJ2kcA0+px/Oku0Y+lAaYNgXphsxoPoMpUNoDuh1GC64Jydr0Siw== X-Received: by 2002:a17:90b:3d84:b0:27d:b488:92ee with SMTP id pq4-20020a17090b3d8400b0027db48892eemr1010911pjb.2.1697686512933; Wed, 18 Oct 2023 20:35:12 -0700 (PDT) Received: from [192.168.0.4] ([71.212.149.95]) by smtp.gmail.com with ESMTPSA id b12-20020a17090acc0c00b0027d12b1e29dsm623740pju.25.2023.10.18.20.35.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 18 Oct 2023 20:35:12 -0700 (PDT) Message-ID: <546ec2af-08be-4fb6-b745-e4ba4d4b91a8@linaro.org> Date: Wed, 18 Oct 2023 20:35:10 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 13/18] target/i386: split eflags computation out of gen_compute_eflags Content-Language: en-US To: Paolo Bonzini , qemu-devel@nongnu.org References: <20231014100121.109817-1-pbonzini@redhat.com> <20231014100121.109817-14-pbonzini@redhat.com> From: Richard Henderson In-Reply-To: <20231014100121.109817-14-pbonzini@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::1036; envelope-from=richard.henderson@linaro.org; helo=mail-pj1-x1036.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 10/14/23 03:01, Paolo Bonzini wrote: > The new x86 decoder wants to compute EFLAGS before writeback, which > can be an issue for some instructions such as ARPL. Extract code > to compute the EFLAGS without clobbering CC_SRC, in case the ARPL > memory write causes a fault. > > Signed-off-by: Paolo Bonzini > --- > target/i386/tcg/translate.c | 18 +++++++++++++----- > 1 file changed, 13 insertions(+), 5 deletions(-) > > diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c > index e13bf7df591..2da7c357cdc 100644 > --- a/target/i386/tcg/translate.c > +++ b/target/i386/tcg/translate.c > @@ -872,18 +872,20 @@ static void gen_op_update_neg_cc(DisasContext *s) > tcg_gen_movi_tl(s->cc_srcT, 0); > } > > -/* compute all eflags to cc_src */ > -static void gen_compute_eflags(DisasContext *s) > +/* compute all eflags to reg */ > +static void gen_mov_eflags(DisasContext *s, TCGv reg) > { > TCGv zero, dst, src1, src2; > int live, dead; > > if (s->cc_op == CC_OP_EFLAGS) { > + if (reg != cpu_cc_src) { > + tcg_gen_mov_tl(reg, cpu_cc_src); > + } tcg_gen_mov_tl already takes care of eliding the nop move. > return; > } > if (s->cc_op == CC_OP_CLR) { > - tcg_gen_movi_tl(cpu_cc_src, CC_Z | CC_P); > - set_cc_op(s, CC_OP_EFLAGS); > + tcg_gen_movi_tl(reg, CC_Z | CC_P); > return; > } > > @@ -909,7 +911,13 @@ static void gen_compute_eflags(DisasContext *s) > } > > gen_update_cc_op(s); > - gen_helper_cc_compute_all(cpu_cc_src, dst, src1, src2, cpu_cc_op); > + gen_helper_cc_compute_all(reg, dst, src1, src2, cpu_cc_op); > +} You don't want to gen_update_cc_op. I think you want TCGv_i32 cc_op = cpu_cc_op; if (s->cc_op != CC_OP_DYNAMIC) cc_op = tcg_constant_i32(s->cc_op); gen_helper_cc_compute_all(..., cc_op); No write to cpu_cc_op required at all, since... > +/* compute all eflags to cc_src */ > +static void gen_compute_eflags(DisasContext *s) > +{ > + gen_mov_eflags(s, cpu_cc_src); > set_cc_op(s, CC_OP_EFLAGS); > } ... this will modify it again anyway. r~